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Physical Review A

Quantum-state-dependent chemistry of ultracold Li62 dimers

Gene Polovy, Erik Frieling, Denis Uhland, Julian Schmidt, Kirk W. Madison

Published Jul 13, 2020• 10 citations
Publisher

Abstract

Starting from an ultracold ensemble of ${}^{6}{\mathrm{Li}}_{2}$ Feshbach molecules, we produce deeply bound triplet $a(1{\phantom{\rule{0.16em}{0ex}}}^{3}{\mathrm{\ensuremath{\Sigma}}}_{u}{}^{+})$ molecules in a single quantum state by stimulated Raman adiabatic passage. The ensemble lifetime is found to be limited by two-body molecule-molecule collisions that depend on both the vibrational and rotational states. The loss rate observed is near the universal rate for the $|v=0,5,8;N=0,2\ensuremath{\rangle}$ states and, remarkably, below universality for the $|v=9,N=0\ensuremath{\rangle}$ state. We also observe a strong rotational state dependence of the $v=9$ reaction rate. Consistent with theoretical predictions, we observe that molecules in the absolute lowest triplet level are unstable and likely decay due to trimer formation.

DOI
10.1103/physreva.102.013310

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We create fermionic dipolar ^{23}Na^{6}Li molecules in their triplet ground state from an ultracold mixture of ^{23}Na and ^{6}Li. Using magnetoassociation across a narrow Feshbach resonance followed by a two-photon stimulated Raman adiabatic passage to the triplet ground state, we produce 3×10^{4} ground state molecules in a spin-polarized state. We observe a lifetime of 4.6 s in an isolated molecular sample, approaching the p-wave universal rate limit. Electron spin resonance spectroscopy of the triplet state was used to determine the hyperfine structure of this previously unobserved molecular state.
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